This article should provide an overview of the main type of diseases that affect the lung. You will find a description of the important diagnostic tests used for investigating respiratory diseases, like general principles, emphasis on lung function testing role and interpretation and examples of diagnostic testing approach for some common presentations.

00:01
Previously I've discussed asthma and COPD in
two previous lectures on airways diseases.
00:07
This third lecture is going to cover other
airways diseases, which are less common butare still significant clinical problems. We're
going to talk about major airways obstruction,bronchiectasis, cystic fibrosis, which is a genetic
disease that is a cause of bronchiectasisand haemoptysis. Diseases that we're going
to discuss today are those that cause largeairways obstruction, and this is physical
obstruction of the central airways, whichI mean, the larynx, the trachea or the major
bronchi. Now clearly, this is an importantarea for conducting air to the lungs, and
if you block the trachea, then you're gonnaget less air ventilating the lungs, and
that is the major significant problem withthese and that's that they are potentially
life-threatening disorders. In addition, theyare easily misdiagnosed as much more common
diseases such as asthma or COPD. When youhave common diseases like those two causes
of airways diseases, asthma and COPD, it'squite easy to think that anybody presenting
with airways obstruction, cough could haveasthma or COPD and forget about things like
larger airways obstruction which will be presentin a very small minority of patients presenting
with those symptoms. So you do need a highindex of suspicion to make sure that you don't
miss these diseases.
01:25
So what are the causes and how do people present
who have large airways obstruction? Well,this depends to a certain degree on the speed
of presentation. So somebody suddenly presentswith airways obstruction, very acute breathlessness
and stridor inspiratory wheeze then you needto think about aspiration of a foreign body
or a large object lodging in the trachealand major bronchus that's been dislodged or
has been aspirated by the patient. In addition,it could be a mucous plug, but they would only
normally clog off a large airway if there'sa pre-existing stricture of some description.
So it's basically a mucous plug on top ofan another cause of airways obstruction and can
present with sudden acute dyspnea and stridor.
02:15
The causes of acute airways obstruction which
are not quite so sudden, but develop rapidlyover hours or days include infection such
as epiglottitis, and abscess of the tonsiland diphtheria and then acute deteriorations
of the chronic causes and the more sub-acutecauses of airways obstruction, and occasionally
smoke inhalation will cause airways oedemawhich will cause upper airways obstruction
but clearly the diagnosis of that is obviousbecause the patient has been recently exposed
to a fire etc. So somebody presenting withthe less hyperacute airways obstruction, again
it's breathlessness, again it's stridor.
02:54
They also may have saliva drooling because they
are unable to swallow, to get rid of theirsaliva and if it is an infective cause, there
will be a temperature. The other causes ofairways obstruction that we need to think
about here are the ones which are sub-acute,the progressive, and less acute causes which
build up over a period of weeks or months.
03:16
Now these tend to be diseases that get worse
slowly but surely over time and hence thedisease symptoms get worse over time and then
they can present with acute obstruction becausethey finally tipped over the edge to be severe
enough to cause that or a sputum plug hasclogged off a partial obstruction. And the
diseases we're thinking about here, the oneswe really need to not miss are those of cancer.
Cancer of the lung, invading the tracheal ormajor airways, larynx and the thyroid gland
doing similar things in the upper part ofthe airways. Benign tracheal tumors such as
carcinoids, massive mediastinal node involvementby a tumor, lymphoma or by lung cancer for
example. Vocal cord paralysis, for exampleif you have a left recurrent laryngeal nerve
palsy. Those sort of things can present, slowlyprogressing obstruction. Then there are
a range of diseases where youmay have a stenosis in the trachea or in the
bronchi, but that's a fixed stenosis, it doesn'tchange much over time, it has occurred in the
past due to some form of disease and it'snow fixed at a certain level. And those situations
it often happens after somebody has had aT-tube and a tracheal tube in for a long period
of time. You can an inflammatory stricturethat stays constant thereafter. And the same
thing happens after some infections, tuberculosisbeing the classic example and the same thing
can happen if somebody has an enlarge thyroidgland due to benign reasons such as goiter.
These patients presenting with a less acuteforms of airways obstruction, they're going
to have dyspnoea, cough. They may cough upblood, especially if there is tumor involvement
and they may get stridor but this will beintermittent, it's only present in certain
positions or when the patient is slightlyworse for whatever reasons. And if you have
an obstruction to a major bronchus, then youcan get pneumonia behind that or bronchiectasis
developing and therefore they might developsymptoms as a consequence of that. If you have
a tumor in the middle of the chest affectingthe trachea, it could also affect other parts
of the mediastinum and therefore you can getother evidence of mediastinal disease such as
esophageal involvement of dyshphagia, potentiallypain, potentially a neurological involvement
of the phrenic nerve or paralysis of a diaphragm,

About the Lecture

The lecture Large Airways Obstruction: Causes by Jeremy Brown, PhD is from the course Airway Diseases.

Included Quiz Questions

Which of the following is NOT a cause of acute large airway obstruction?

Foreign body aspiration

Epiglottitis

Tonsillar abscess

Tracheal oedema due to smoke inhalation

Diptheria

Which of the following is an example of acute obstruction of large airway?

Diptheria

Goitre

Tracheomalacia

Vasculitis

Post intubation tracheal stenosis

Author of lecture Large Airways Obstruction: Causes

Jeremy Brown, PhD

Customer reviews

(1)
5,0 of 5 stars

5 Stars

5

4 Stars

0

3 Stars

0

2 Stars

0

1 Star

0

User Reviews

(1)
5,0 of 5 stars

5 Stars

5

4 Stars

0

3 Stars

0

2 Stars

0

1 Star

0

Subscribe to bookmark your content

Bookmarks will help you organize our more than 2000 medical videos,
and customize your learning experience for more efficiency and better results.

USMLE™ is a joint program of the Federation of State Medical Boards
(FSMB®) and National Board of Medical Examiners (NBME®). MCAT is a registered
trademark of the Association of American Medical Colleges (AAMC).
None of the trademark holders are endorsed by nor affiliated with Lecturio.